Means for coating metallic articles, particularly the interiors of water mains



May 12, 1931. F. w. HAMMOND 1,305,215

MEANS FOR COATING METALLIC ARTICLES, PARTICULARLY THE INTERIORS OF WATERMAINS (IN SITU) Filed May 13, 1930 2 Sheets-Sheet 1 wfw F 05 emf I/Kflaw/vamp May 12, 1931. w HAMMOND 1,805,215

MEANS FOR COATING METALLIC ARTICLES, PARTICULARLY THE INTERIORS OF WATERMAINs (IN SITU) V Filed May 15, 1930 2' Sheets-Sheet 2 Patented May 12,1931 tain a percentage I prevent such re-growth UNITED STATES PATENTOFFICE FREDERICK witnim-mmonmor c mrs'row, ENGLAND means roa commaMETALLIC narrows; PARTICULARLY rim INTERIORS or warm MAINS n SITU) IApplication filed May 13, 1930, Serial No. 452,118, and in Great BritainMarch 5, 1930.

This invention provides improved means for depositing a protectivecoating on metallic articles, particularly the interior surfaces ofwater mains (in situ) including a colloidal solution or emulsion offiuxed bitumen and other ingredients in an aqueous medium from which thesaid coating is deposited by electrolysis between an anode consisting ofthe positively charged metallic article to be coated and a negativelycharged cathode which is movable opposite to and along the surfaces ofsaid metallic articles,.

and a source of direct electric current.

Ithas been found in practice that after scraping and clearing away thedeposits of Organic and inorganic grounds in water mains, fresh depositsset up very quickly, due to inferior pipes or pipes with inferiorbituminous coating and to the action of the water conveyed, with theresult that ob ectionable discoloured water is supplied and an importantobject of this invention is' to of deposits and discolouration of thewater.

The present invention therefore provides a protective solution oremulsion containing fluxed bitumen and other ingredients and apparatuswhereby the said solution or emulsion is de osited by electrolysis onthe surfaces of t e metallic articles so as to leave a smooth andcoherent continuous coating,

impervious to water, of colloidal particles of bitumen with otherprotective ingredients.

The electrolytic coating is deposited from a colloidal solution oremulsion which ncludes pure petroleumbitumen fiuxed with asphalt oiland/or paraffin wax, with or without a percentage of saponaceous material plus a protective adhesive colloid such as casein, gum or strach asemulgent.

In certain cases the electrolytic solution may'include pure petroleumbitumen fluxed with asphalt oil and have a percentage of casein, gum orstrach, or in addition to the foregoing ingredients the solution mayconof saponaceous material.

In other cases the electrolyte may include pure petrolum bitumen fluxedwith asphalt oil and parafiin wax of either one of these fluxes and havea percentage of casein, gum

or strach as adhesive and emulgent, or in ad-- The fiuxed bitumencontent of the electrolytic solution is approximately 25% of the totalweight of the. solution, and of the other ingredients when included,from 0.25% to 0.5% of alkali, from 0.25% to 0.5% of fatty acid, from0.05% to 0.1% of casein, gum or strach.

The electrolyte is applied by partial. or total immersion or byspraying, to the article to be coated which is connected as one of theelectrodes to one pole of a dynamo while the other electrode, which isof shape or section conforming suitably to that of the articles to becoated, contains or is immersed in the electrolyte and is connected tothe other pole of the dynamo;

The article to be coated is connected to the positive pole of the dynamoas anode, and the shaped electrode to the negative pole as cathode, thelatter, when water pipes are to be coated, being a metallic tube orcylinder -mounted on a carriage of insulating material-and caused totravel through the water pipes which are first filled with theelectrolyte, or the latter may alternately be sprayed in jets from thenegatively charged cathode as it travels through the water pipes or acathode sealed at each end by hydraulic washers and carrying its ownsupply of electrolyte fed by a hosepipe as it travels or is drawnthrough the water pipes, ma be used.

In order that the invention may e clearly understood, there will now bedescribed with the aid of the accompanying drawings, variousmodifications of the apparatus suitable for metal articles of differentkinds and sizes.

In the drawin s:

Figure 1 is a iagram showing the-appli-v cation of the process to metalarticles generally.

Figures 2 and 3.are longitudnal and cross sections respectively of awater pipe of small diameter, to be filled with the electrolyte and withsuitable apparatus therein.

Figures 4 and-5 are longitudinal and cross sections respectively ofawater which are of moderate size and compact shape, a suitable vessel 1contains the electrolytic solution, the article 2 which is to be coatedand which is connected to the positive pole 3 of the electric supply,and also the negatively charged cathode 4 which is connected to thenegative pole 5. The cathode 4 may be moved opposite to and along'thesurfaces of the article 2 when the latter is of sufficient area orextent torequire such movement. A voltmeter 6 and ammeter 7 are providedin the circuit in order that the electric supply may be regulatedthrough the electrolyte. v

For water pipes of small or moderate diameter, as shown in Figures 2 and3, the pipe 8. is to be filled with the electrolyte from a tank or byother suitable means, and into the pipe 8 there is introduced acylinder9 preferably of copper as the negatively charged cathode which isarranged to 'be drawn through the pipe 8 by a cord or wire rope fixed toan msulating bridge-piece 10.. A carriage 11 of insulating material,such as hardwood, supports the cylinder 9 and is fitted with rubberdiscs or rings 12 to centre the cylinder 9 in the pipe 8 and tofacilitate its passage therethrough. The rings 12 are perforated or havescalloped edges to allow free passage of the cathode 9 through theelectrolyte, but the rings are staggered so that the perforations arenot in direct alignment to prevent the pipe 8 being coated imperfectlyahead of the cathode 9. Four of the rings 12 are generally employed butthese may be added to with advantage for larger ipes.

' Waterproof cable '13 is connected to a terminal 14 on the front end ofthe carriage 11 and a central conductor 15 connects between the terminal14 and the cylinder 9 via a flexible lead 16. There is a wooden boss 17at the rear .of the cylinder 9 to prevent it from touching the walls ofthe 'pipe 8 and so makr ing a short-circuit for the current.

Referring nowto Figures 4 and 5, the cathode 18 is for use with pipeswhich are too large to be easily filled with electrolyte and it has atthe ends carriages l9 and 20 of insulating material, such as hardwood,which are fitted with rubber discs or rings 21 and leather hydraulicwashers 22 which centre and insulate the cathode 18 in. the water whichis carried between the cathode 18 the water pipe 23;

The electrolyte is fed through a hosepipe 24 to a tube 25 runningthrough the front and carriage 19 and emerging through the surface ofthe cathode'cylinder-18, any surplus being allowed to escape past therear rubber ring 21, and hydraulic washer 22. This is necessary tomaintain the concentration of bitumen required in the electrolyte in usebetween the cathode cylinder 18 and the water pipe 23.

The numbers of rubber rings and hydraulic washers used depend on thesize of the water pipe to be coated, being one or more of each percarriage.

a Means of supplying electric current and means of hauling through theWater pipe are provided as hereinbefore described and the cathodes arein all cases to be drawn through their respective pipes at such a speedas "will ensure correct deposition-of the bitumen particles.

Referring now to Figures 6 and 7, which illustrate an apparatus forcoating pipes large enough to admit of the ingress of a man, the cathodeis a brass plate 26 curved to the shape of the inner surface ofthe waterpipe 27 and is held in a box 28 of insulating'material, such ashardwood, similarly curved to the pipe 27; the cathode plate 26 isinsulated from the pipe 27 by a flexible rubber edging 29 which alsoserves as a seal for the electrolyte between the pipe 27 and the oathodeplate 26.

A supply tube 30 isarticulated to the box 28 and conveys a supply ofelectrolyte from a suitable reservoir to thebox 28 and to the I spacebetween the cathode plate 26 and the inner surface of the water pipe 27via a hose pipe 31 and a short tube 32 emerging through the surface ofthe cathode plate 26; a valve 33 is provided at the top end of the tube30 to control the flow of the electrolyte. The tube 30 is universallyjointed by being held by a ball 34 between two cups 35iand 36 midwaybetween two wood-wheeled trolleys 37 and 38 forming a travellingcarriage and being held against the top and bottom of the pipe 27 by twotelescopic screwed struts 39 and 40 capable of being extended orcontracted by twqhand nuts 41 and 42, enabling the apparatus to beadjusted to the diameter of the pipe. y

Electric currbnt is provided and is supplied to the cathodeplate 26 bycable 43 connected to said plate 26 through box'28 and is controlled byand switch 45. 3

, A third telescopic screwed strut 46 behind- 27 and controlled by 'thehand nut 47 and fitted with a friction pad 48, enables the cathode plateand box 28 to be firmly held against cany' desired portion of theinterior surface the ammeter 44 the waterproof of the water pipe 27, theball 34 and cups 335 and 36 controlling radialmovement and the trolleys37 and 38 controlling longitudinal movement in the pipe 27.

The pipe 27 can be coated at any desired part by straining the box 28 tothe interior surface of the pipe 27, flooding the space between thecathode plate 26 and the pipe 27 and switching on the electric currentfor such a period of time as will ensure correct deposition of thebitumen particles.

The electric supply may be from a portable dynamo or from public supplymains giving direct current at about 100 to 110 volts whilst the currentstarts at about 0.16 amperes per square inch of surface to be coated andfalls to a lower figure as the surface becomes coated.

I claim 1. Improved means for depositing a pro tective coating onmetallicarticles, including a colloidal solution or emulsion or fiuxedbitumen and other ingredients in an aqueous medium from which saidcoating is deposited by electrolysis, an anode consisting of thepositively charged water pipe to be coated, a

' cathode consisting of a negatively charged tective coating on metallicarticles, including a colloidal solution or emulsion or fluxed bitumenand other ingredients in an aqueous medium from which said coating isdeposited by electrolysis, an anode consisting of the positively chargedwater pipe to be coated, a cathode consisting of a negatively chargedcopper cylinder having at the ends travelling carriages of insulatingmaterial fitted with rubber discs or rings and leather washers, asupply. of electrolyte sealed between said rings and washers, a hosepipefeedin said electrolyte to a tube running through the front carriage andemerging through the surface of the cathode cylinder, a waterproof cableconnected to a terminal on front carria e, a conductor and flexible leadbetween sai terminal and cathode cylinder, and a source of directelectric current.

3. Improved means for depositing'a prote'ctive coating on metallicarticles, including a colloidalsolution or emulsion of fiuxed bitumenand other ingredients in an aqueous medium from which said coating isdeposited by electrolysis, an anode consisting of the positively chargedwater pipe to be coated, a cathode consisting of a negatively chargedmetal plate curved to the inner surface of said water pipe, a box ofinsulating material holding said cathode plate and similarly curved,flexible rubber edging between said cathode plate'and water pipe, asupply tube articulated to said box conveying a supply of electrolytefrom a reservoir to the space between said cathode plate and the innersurface of the water pipe via a hosepipe and a tube emerging through thesurface of the cathode plate-and universally jointed by a ball and twocups between two trolleys, a travelling carriage formed of said trolleyswhich have wood wheels held against the top and bottom of the water pipeby two telescopic screwed struts on either side of said ball and cupsand capable of being extended or contracted by two hand nuts to suit thediameter of the water pipe, a third telescopic screwed strut between thetop of said supply tube and the water pipe controlled by hand nut andfitted with a friction pad to enable the cathode box and plate to beheld against any portion of the water pipe by said ball and cupscontrolling radial movement and said trolleys controlling longitudinalmovement, a waterproof cable connected to the cathode plate and a sourceof direct electric current.'

In testimony whereof I have aflixed my signature heretothis 23rd day ofApril 1930,

FREDERICK WILLIAM HAMMOND.

